1. Field of the Invention
The present Invention relates to a rheumatism scanner of the type having a hand rest that is arranged between a radiation source and a detection unit and with a holding unit for immobilizing a finger joint to be examined on the hand rest.
2. Description of the Prior Art
The examination of joints of the finger With a rheumatism scanner has posed considerable problems and has been extremely time-consuming, regardless of the radiation source used to conduct the examination. Experience has shown that a typical rheumatic patient cannot keep his or her hand still, so that immobilization of the joint over the period of the exam is very important. Conventionally, the finger joint is usually fixed on a hand rest by fastening the fingers with the aid of clamping bands. These provide an unsatisfactory and unreliable fastening, however. Furthermore, the distance from the fingertip to the lower finger joint must be measured with a sliding gage before every scan, and the measurement value must be entered into the PC, so that, given placement of the finger at a detent on the hand rest, the exact examination in the joint gap will actually occur. Subsequent to the entry of the measurement value and the fixing of the finger, a step motor extends the positioned joint gap relative to an optical measuring axis. Each finger must be so measured and positioned with the step motor. This leads to very long examination times and to an equally long occupation of the rheumatologist, who must perform the measuring, the positioning and the examination.